Method of Collecting Information for a Geographic Database for use with a Navigation System

ABSTRACT

A method of collecting data for a geographic database for use with a navigation system is disclosed. A feature visible from a road segment is identified. A guidance feature point object is defined at a location at the road segment where the identified feature is most visibly prominent. Additionally, an importance rating and a preferred name for the identified feature are determined. Data representing the guidance feature point object, importance rating and the preferred name are stored in the geographic database on a computer readable medium.

REFERENCE TO RELATED APPLICATIONS

The present application is related to the co-pending applicationentitled “METHOD OF OPERATING A NAVIGATION SYSTEM TO PROVIDE ROUTEGUIDANCE” filed on the same date herewith, Attorney Docket No. N0320US,the entire disclosure of which is incorporated by reference herein. Thepresent application is related to the co-pending application entitled“METHOD OF OPERATING A NAVIGATION SYSTEM TO PROVIDE ROUTE GUIDANCE”filed on the same date herewith, Attorney Docket No. N0321US, the entiredisclosure of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a method and system for operating anavigation system, and more particularly to a method and system forproviding route guidance using contextual elements along a calculatedroute from an origin location to a destination location.

Navigation systems are available that provide end users with variousnavigation-related functions and features. For example, some navigationsystems are able to determine an optimum route to travel along a roadnetwork from an origin location to a destination location in ageographic region. Using input from the end user, the navigation systemcan examine various potential routes between the origin and destinationlocations to determine the optimum route. The navigation system may thenprovide the end user with information about the optimum route in theform of guidance that identifies the maneuvers required to be taken bythe end user to travel from the origin to the destination location. Somenavigation systems are able to show detailed maps on displays outliningthe route, the types of maneuvers to be taken at various locations alongthe route, locations of certain types of features, and so on.

In order to provide these and other navigation-related functions andfeatures, navigation systems use geographic data. The geographic datamay be in the form of one or more geographic databases that include datarepresenting physical features in the geographic region. The geographicdatabase includes information about the represented geographic features,such as one-way streets, position of the roads, speed limits alongportions of roads, address ranges along the road portions, turnrestrictions at intersections of roads, direction restrictions, such asone-way streets, and so on. Additionally, the geographic data mayinclude points of interests, such as businesses, facilities,restaurants, hotels, airports, gas stations, stadiums, police stations,and so on.

Although navigation systems provide many important features, therecontinues to be room for new features and improvements. One area inwhich there is room for improvement relates to providing guidance tofollow a route. Typically, route guidance identifies maneuvers to betaken at specified locations, such as turn left at next intersection.Some end users may get confused as to their orientation and where toturn. Accordingly, it would be beneficial to provide improved guidanceto follow a route.

More particularly, it would be beneficial to consider details in the enduser's environment and context to provide a more natural, environmentaland intuitive guidance message.

SUMMARY OF THE INVENTION

To address these and other objectives, the present invention comprises amethod of collecting data for a geographic database for use with anavigation system. The method identifies a feature visible from a roadsegment. A guidance feature point object is defined at a location at theroad segment where the identified feature is most visibly prominent.Additionally, an importance rating and a preferred name for theidentified feature are determined. The importance rating indicates alevel of visual distinctiveness of the identified feature as compared toother features surrounding the identified feature. The preferred name isselected from a group consisting of a color of the identified feature, abuilding material of the identified feature, a shape of the identifiedfeature, an architectural style of the identified feature, and adecorative element of the identified feature. Data representing theguidance feature point object is stored in the geographic database on acomputer readable medium. Additionally, the importance rating and thepreferred name for the identified feature are stored in the geographicdatabase on the computer readable medium.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention is described hereinwith reference to the following drawings.

FIG. 1 is a block diagram of a navigation system, according to anexemplary embodiment.

FIG. 2 shows a map of a geographic region.

FIG. 3 is a block diagram of a geographic database that represents thegeographic region included in the navigation system depicted in FIG. 1

FIG. 4 is a block diagram of components of data records contained in thegeographic database depicted in FIG. 3.

FIG. 5 is a flow chart for collecting environmental context informationuseful for guidance instructions.

FIGS. 6 a and 6 b are representations of portions of the geographicregion. FIG. 7 is a table illustrating importance attributes for afeature in the geographic region.

FIG. 8 is a block diagram of components of data records contained in thegeographic database.

FIG. 9 a is a flow chart for providing a passing guidance message.

FIG. 9 b is a representation of a portion of the geographic region.

FIG. 10 is a flow chart for providing a junction guidance message.

FIG. 11 is a representation of a portion of the geographic region.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

I. Navigation System

FIG. 1 is a block diagram of a navigation system 100 associated with acomputing platform 102, such as an in-vehicle navigation device, apersonal navigation device, a mobile computer, mobile telephone,personal digital assistant (PDA), personal computer, or any othercomputer, according to an exemplary embodiment. The navigation system100 is a combination of hardware and software components. In oneembodiment, the navigation system 100 includes a processor 104, a drive106 connected to the processor 104, and a non-volatile memory storagedevice 108 for storing navigation application software programs 110 andpossibly other information.

The navigation system 100 also includes a positioning system 112. Thepositioning system 112 may utilize GPS-type technology, a deadreckoning-type system, or combinations of these or other systems, all ofwhich are known in the art. The positioning system 112 may includesuitable sensing devices that measure the traveling distance speed,direction, orientation and so on. The positioning system 112 may alsoinclude a GPS system. The positioning system 112 outputs a signal to theprocessor 104. The navigation application software programs 110 that runon the processor 104 use the signal from the positioning system 112 todetermine the location, direction, orientation, etc., of the computingplatform 102.

The navigation system 100 also includes a user interface 114 that allowsthe end user to input information into the navigation system 100 andobtain information from the navigation system 100. The input informationmay include a request for navigation features and functions of thenavigation system 100. To provide navigation features and functions, thenavigation system 100 uses a geographic database 116 stored on acomputer readable storage medium 118. In one embodiment, the storagemedium 118 is installed in the drive 106 so that the geographic database116 can be read and used by the navigation system 100. In oneembodiment, the geographic database 116 may be a geographic databasepublished by NAVTEQ North America, LLC of Chicago, Ill. The storagemedium 118 and the geographic database 116 do not have to be physicallyprovided at the location of the navigation system 100. In alternativeembodiments, the storage medium 118, upon which some or the entiregeographic database 116 is stored, may be located remotely from the restof the navigation system 100 and portions of the geographic dataprovided via a communications system 120, as needed.

In one exemplary type of system, the navigation application softwareprograms 110 load from the non-volatile memory storage device 108 into arandom access memory (RAM) 122 associated with the processor 104. Theprocessor 104 also receives input from the user interface 114. Thenavigation system 100 uses the geographic database 116 stored on thestorage medium 118, possibly in conjunction with the outputs from thepositioning system 112 and the communications system 120, to providevarious navigation features and functions. The navigation applicationsoftware programs 110 may include separate applications (or subprograms)that provide the various navigation-related features and functions. Thenavigation functions and features may include route calculation 124(wherein a route from an origin to a destination is determined), routeguidance 126 (wherein detailed directions are provided for reaching adesired destination), map display 128 (wherein a map depicting thecurrent position and route to travel are shown on a display), andpositioning 130 (e.g., map matching). Other functions and programming132 may be included in the navigation system 100 including people andbusiness finding services (e.g., electronic yellow and white pages),point of interest searching, destination selection, and location baseadvertising services.

The navigation application software programs 110 may be written in asuitable computer programming language such as C, although otherprogramming languages, such as C++ or Java, are also suitable. All ofthe components described above may be conventional (or other thanconventional) and the manufacture and use of these components are knownto those of skill in the art.

In alternative embodiments, the navigation system 100 includes localcomponents, located physically with an end user, that communicate withremote components, located remotely from the end user. In thisembodiment, the remote components include a navigation services server.The navigation application software programs 110 and the geographicdatabase 116 reside with the navigation server. The local components ofthe navigation system communicate with the remote components via acommunication link. The communication link may use any suitabletechnology and/or protocols that are currently available, as well astechnology and/or protocols that become available in the future. Aportion of the communications link may include a wireless portion thatenables two-way communication between the local components and theremote components. The wireless portion may be implemented by anysuitable form of wireless communication, including cellular, PCS,satellite, FM, radio, Bluetooth®, other long and short rangetransmission technologies or technologies that may be developed in thefuture.

II. Geographic Database

In order to provide navigation-related features and functions to the enduser, the navigation system 100 uses the geographic database 116. Thegeographic database 116 includes information about one or moregeographic regions. FIG. 2 illustrates a map 200 of a portion of ageographic region 202. The geographic region 202 may correspond to ametropolitan or rural area, a state, a country, or combinations thereof,or any other area. Located in the geographic region 202 are physicalgeographic features, such as roads, points of interest (includingbusinesses, municipal facilities, etc.), lakes, rivers, railroads,municipalities, etc.

The map 200 illustrates part of a road network in the geographic region202. The road network includes, among other things, roads andintersections located in the geographic region 202. Each road in thegeographic region 202 is composed of one or more road segments 204. Aroad segment 204 represents a portion of the road. Each road segment 204is shown to have associated with it two nodes 206; one node representsthe point at one end of the road segment and the other node representsthe point at the other end of the road segment. The node 206 at eitherend of a road segment 204 may correspond to a location at which the roadmeets another road, i.e., an intersection, or where the road dead-ends.The road segments 204 may include sidewalks and crosswalks for travel bypedestrians.

As shown in FIG. 2, the geographic region 202 also includes complexfeatures 208, such as a complex intersection that comprises multipleroad segments and multiple nodes. The geographic region further includespoints of interest 208, such as businesses, facilities, restaurants,hotels, gas stations, stadiums, police stations, and so on. Thegeographic region 202 further includes other cartographic features 210,such as lakes, forests, rivers, hills, mountains and so on.

Referring to FIG. 3, the geographic database 116 contains data 302 thatrepresents some of the physical geographic features in the geographicregion 202 depicted in FIG. 2. The data 302 contained in the geographicdatabase 116 includes data that represent the road network for travel byvehicles and the pedestrian network for travel by pedestrians. In theembodiment of FIG. 3, the geographic database 116 that represents thegeographic region 202 contains at least one road segment data record 304(database record may also be referred to as “entity” or “entry”) foreach road segment 204 in the geographic region 202. The geographicdatabase 116 that represents the geographic region 202 also includes anode data record 306 for each node 212 in the geographic region 202. Theterms “nodes” and “segments” and “links” represent only one terminologyfor describing these physical geographic features, and other terminologyfor describing these features is intended to be encompassed within thescope of these concepts.

The geographic database 116 also contains complex feature data records306 that represent complex features, such as complex intersections orgrouped features that contain multiple road segments and nodes. Thegeographic database 116 further contains cartographic feature datarecords 310 that represent cartographic features, such as lakes, rivers,railroads, airports, parks, woodland and so on. The geographic database116 also contains point of interest data records 312 that representpoints of interest, such as businesses, facilities, restaurants, hotels,gas stations, stadiums, police stations, and so on. The point ofinterest data may include point of interest records comprising a type ofpoint of interest, location of the point of interest, a phone number,hours of operation, etc.

Moreover, the geographic database 116 contains guidance feature pointobject data records 314 and association data records 316 that will bedescribed in detail below. The geographic database 116 may also includeother kinds of data. The other kinds of data 312 may represent otherkinds of geographic features or anything else. The geographic database116 also includes indexes 318. The indexes 318 may include various typesof indexes that relate the different types of data to each other or thatrelate to other aspects of the data contained in the geographic database116. For example, the indexes 318 may relate the nodes in the node datarecords 306 with the end points of a road segment in the road segmentdata records 304. As another example, the indexes 314 may relate pointof interest data in the point of interest data records 312 with a roadsegment in the road segment data records 304.

FIG. 4 shows some of the components of a road segment data record 304contained in the geographic database 116. The road segment data record304 includes a segment ID 304(1) by which the data record can beidentified in the geographic database 116. Each road segment data record304 has associated with it information (such as “attributes”, “fields”,etc.) that describes features of the represented road segment. The roadsegment data record 304 may include data 304(2) that indicate a speedlimit or speed category (i.e., the maximum permitted vehicular speed oftravel) on the represented road segment. The road segment data record304 may also include data 304(3) that indicate a classification such asa rank of a road segment that may correspond to its functional class.The road segment data record also includes data 304(4) that indicatewhether a sidewalk is associated with the road segment as well asattributes information for the sidewalk. The road segment data record304 may also include or be associated with other data 304(6) that referto various other attributes of the represented road segment. The variousattributes associated with a road segment may be included in a singleroad segment record, or may be included in more than one type of recordwhich cross-references to each other. For example, the road segment datarecord 304 may include data identifying what turn restrictions exist ateach of the nodes which correspond to intersections at the ends of theroad portion represented by the road segment, the name or names by whichthe represented road segment is known, the length of the road segment,the grade of the road segment, the street address ranges along therepresented road segment, the permitted direction of vehicular travel onthe represented road segment, whether the represented road segment ispart of a controlled access road (such as an expressway), a ramp to acontrolled access road, a bridge, a tunnel, a toll road, a ferry, and soon.

The road segment data record 304 also includes data 304(6) identifyingthe endpoints of the road segment and the location (e.g., the latitudeand longitude) of the endpoints. In one embodiment, the endpoint data304(6) references node data records 306 defined for the nodescorresponding to the endpoints of the represented road segment. Byconvention, each road segment is considered to have a “reference” or“left: endpoint and a “non-reference” or “right” endpoint. The leftendpoint may be the node having greater longitudinal coordinates, or inthe case in which the longitudinal coordinates are the same, the nodehaving the lesser latitude. Of course, which node is defined as the leftor right endpoints can be alternatively defined.

Each node data record 306 includes a node ID 306(1) by which the recordcan be identified in the geographic database 116. The node data record306 also includes data 306(2) data identifying the geographiccoordinates (e.g., the latitude, longitude, and optionally altitude) ofthe represented node. The node data record 306 also includes data 306(3)identifying road segments that connect to the node to form anintersection. For example, a node identified by a node ID 306(1) mayrepresent an intersection of two roads. At the intersection, each of thetwo roads may be represented by two road segments (located on oppositesides of the center of the intersection) each having an endpoint at thenode. In this example of a standard four-way intersection, theconnecting segment data 306(3) includes four segments IDs 304(1)identifying the four road segments that connect to the node to form theintersection.

The node data record 204 also include data 306(4) that indicate whethera crosswalk is present as well as attributes information for thecrosswalk. The node data record 306 may also include other data 306(5)that refer to various other attributes of the nodes.

III. Collecting Data for Guidance Feature Points and AssociationInformation

It is desired to provide support for end user to get route guidanceinstructions based on contextual elements surrounding the road segment.Such enhanced guidance is referred to as natural guidance, and naturalguidance is defined as a turn-by-turn experience encompassing multipleattributes and relations which details the user's environment andcontext to more natural, environmental and intuitive triggers. Guidancemessages formed using natural guidance provide details of contextualelements surrounding decision points such as points of interest,cartographic features and traffic signals and/or stop signs. An exampleof a guidance message using natural guidance is “go past the domebuilding on your right, then turn right after the petrol station.”

To allow the navigation system 100 to provide natural guidanceinformation, a geographic database developer collects informationrelating to the geographic features of the geographic region useful forproviding guidance instructions that are more natural, provideadditional environmental context and are more intuitive. In oneembodiment, a geographic researcher travels the geographic region tocollect information relating to geographic features. As the geographicresearch travels the geographic region, images and/or video of the roadnetwork and the area surrounding the road are collected and stored on astorage medium. The geographic research collects information directlywhen traveling in the geographic region and/or collects informationafter traveling in the geographic region by later examining the videoand images. In another embodiment, the geographic researcher uses aerialimages to collect information.

FIG. 5 illustrates a flow chart of the steps for collectingenvironmental context information useful for natural guidance. Thegeographic researcher uses a computer work station, comprising a userinterface, a display, a processor and a computer readable storage,medium to carry out the steps of this flow chart. Although the steps forcollecting environmental context information useful for natural guidanceare described in terms of road segments, similar steps may be used tocollect environmental context information useful for pedestrians.Additionally, may road segments include sidewalks for travel bypedestrian, so environmental context information collected for the roadsegment may be readily applied to the associated sidewalk for use bypedestrians.

At step 500, the geographic research identifies a feature visible from aroad segment. In one embodiment, the geographic researcher displaysvideo of the road segment including portions of the geographic region ateither side of the road segment on the work station. The feature may bea point of interest, such as a building, and or a cartographic feature,such as a lake. FIG. 6 a illustrates a cartographic feature of a lake600 visible from the road segment 602. FIG. 6 b illustrates points ofinterest of a gas station 610 and a government building 612 proximate acomplex intersection 614 visible from the road segments. The geographicresearcher may identify every feature visible on the road segment or asubset thereof including prominent visible features.

At step 502 of FIG. 5, the geographic researcher creates a guidancefeature point object for the identified feature visible from the roadsegment. A guidance feature point object represents a visible feature ator of a point on a road segment. The guidance feature point object iscreated at a location where the feature is most visibly prominent ormost visibly identifiable or recognizable for the purpose of providingguidance advice referencing the visible feature. When the guidancefeature point object is created, the geographic researcher records thelatitude and longitude (and altitude) position information for theguidance feature object point and indicates on which side of the roadsegment that the visible feature is located. In one embodiment, becausethe guidance feature point object is located at the road segment fromwhich the feature is most visibly prominent, the guidance feature pointobject is not located at an access point, drive way, or entrance pointof the feature and the guidance feature point object is not located at aaddress point location of the feature.

Referring to FIG. 6 a, a guidance feature point object 604 is located onthe road segment 602 at a location where the lake 600 is most visiblefrom the road segment 602.

As shown in FIG. 6 a, trees 606 obstruct the view of the lake 600 atseveral points along the road segment 602; therefore, the guidancefeature point object 604 is located away from the trees 606 to provide aclear view to the lake 600 from the road segment 602. In one embodiment,the feature, such as the lake 600, should be visible from 25 meters ormore on either side of the guidance feature point object 604. In otherembodiments, different distances from either side of the guidancefeature point object are possible, and the speed limit associated withthe road segment may be considered when selecting such distances.Furthermore, if the visible feature is to be used for pedestrianguidance, the distances on either side of the guidance feature pointobject may be reduced because of the slow travel speed of a pedestrian.

Referring to FIG. 6 b, the gas station 610 is proximate to the complexintersection 614 and road segments 620, 622, 624 and 626. The geographicresearcher creates guidance feature point objects 632 and 634 at theroad segments 620 and 622 respectively at locations where the gasstation 610 is most visible without or with limited obstruction from theroad segments 620 and 622. The geographic researcher also creates aguidance feature point objects 636 and 638 at the road segments 624 and626 respectively at locations where the gas station 610 is most visiblewithout or with limited obstruction from the road segments 624 and 626.

Referring to FIG. 6 b, the government building 612 is proximate to thecomplex intersection 614 and road segments 616, 618, 628 and 630. Thegeographic researcher creates a guidance feature point objects 640 atthe road segment 616 at a location where the government building is mostvisible without or with limited obstruction from the road segment 616.The geographic researcher also creates a guidance feature point object642 at the road segment 630 at a location where the government building612 is most visible without obstruction or with limited from the roadsegment 630. Note that the government building 612 is not visible fromroad segments 618 and 628 because high fences 644 and 646 obstruct theview of the government building 612 from those road segments.Accordingly, the geographic researcher does not create guidance featurepoint objects at or on the road segments 618 and 628 corresponding tothe government building 612.

At step 504, the geographic researcher determines whether the createdguidance feature point object is useful to provide passing guidance orjunction guidance. Passing guidance supports route guidance when passinga feature; junction guidance supports route guidance when driving (orturning) over a junction and/or complex intersection. Referring to FIG.6 a, the guidance feature point object 604 may be used to providepassing guidance because it provides a clear view of the lake 600 whenpassing by the lake 600 on the road segment 602. Referring to FIG. 6 b,the guidance feature point objects 632, 634, 636, 638, 640 and 644 maybe used to provide junction guidance because they are proximate andviewable when traveling through or turning at the complex intersection614.

At step 506, the geographic researcher associates the road segments thathave an unobstructed or limited view of the feature with the createdguidance feature point object and thus associated to the feature. Whendetermining which road segments to associate with the guidance featurepoint object, the geographic researcher ensures that it is possible todrive from that road segment (to be associated) onto the road segment atwhich the guidance feature point object is located. For the guidancefeature point object useful for passing guidance, the road segment isassociated with the guidance feature point object located at or on theroad segment. For the guidance feature point object 604 shown in FIG. 6a that is useful for passing guidance, the road segment 602 isassociated with the guidance feature point object 604 and thusassociated with the cartographic feature of the lake 600.

FIG. 6 b illustrates how road segments are associated with guidancefeature point objects useful for junction guidance. The gas station 610is visible from road segments 618, 620, 622, 624, 626 and 628. Roadsegment 620 is associated with guidance feature point object 632, roadsegment 622 is associated with guidance feature point object 634, roadsegment 624 is associated with guidance feature point object 636, androad segment 626 is associated with guidance feature point object 638because these respective guidance feature point objects are located ator on these respective road segments. As for one of the road segmentsthat do not have a guidance feature point object located at or on theroad segment, the road segment from which the feature is visible isassociated with the guidance feature point object that is located on oneof the road segments of the junction that can be driven to from theother road segment. For road segment 628, the gas station 610 is visibleand a vehicle may drive from road segment 628 onto road segment 626.Accordingly, road segment 628 is associated with the guidance featurepoint object 638 located on road segment 626. The gas station 610 is notvisible from road segments 616 because a high fence 644 obstructs theview of the gas station 610 from road segment 616. Also, the gas station610 is not visible from road segments 630 because a high fence 646obstructs the view of the gas station 610 from road segment 630. Thus,road segments 616 and 630 are not associated with guidance featureobject points related to the gas station 610.

Referring to FIG. 6 b, the government building 612 is visible from roadsegments 616 and 630, and the high fences 644 and 646 obstruct the viewof the government building 612 from road segments 618, 620, 622, 624,626 and 628. The road segment 616 is associated with guidance featurepoint object 640; the road segment 630 is associated with guidancefeature point object 642.

At step 508, the geographic researcher determines a preferred name forthe feature and associates the preferred name with the respectiveguidance feature point object(s) related to that feature. The preferredname describes a visible characteristic or a visually distinguishingaspect of the feature, such as the color of the feature, shape of thefeature, age of the feature, building materials of the feature, style ofthe feature, architectural description, decorative features, othervisual properties including luster and sheen (shiny or dull) of thefeature, motion or perceived motion of a portion of the feature, and/orany visible attribute that distinguishes the feature from other featuresin the surrounding area. For example, the special name may be pinkbuilding, dome-shaped building, glass building, brick building, gothicarchitecture building, windowless building, tall building, neon sign ofa bird attached to building, fountain in front of building, sculpture infront of building, and so on. Furthermore, the preferred name mayinclude various adjectives to describe the feature, such as grand oldcourthouse. In one embodiment, the preferred name may be a locally knowname or nickname for the feature, such as “Max Brothers Petrol Shop.” Inaddition to determining a preferred name for the feature, a base name isdetermined, such as gas station for the gas station 612. In a furtherembodiment, the brand name of the gas station may be determined. Inanother embodiment, different preferred names may be collected fordifferent end users. For example, one preferred name may be collectedfor female end users and another preferred name for male end users; onepreferred name may be collected for local end users and anotherpreferred name for tourists or end users that do not reside is thegeographic region.

At step 510, the geographic research collects information regarding thevisibility, seasonal dependency, relative distance of the feature andcomputes a calculated importance for the feature. The visibility,seasonal dependency and relative distance attribute information alongwith the calculated importance value are associated with the respectiveguidance feature point object(s) of the feature. The visibilityattribute defines how visible or how obscured the feature is whentraveling the road segment. The visibility attribute is assigned one ofthe visibility values that indicate a level of visibility (or level ofvisual obstruction), such as 1 for clearly visible, 2 for partiallyvisible and 3 for not visible. Partial visibility may occur because ofobstructions such as signs, trees, surrounding building, and so on.

For the example shown in FIG. 6 a, the lake 600 for guidance featurepoint object 604 is assigned a visibility value of 2 for partiallyvisible because trees 606 obscure the view of the lake 600 for a portionof the road segment 602. For the example shown in FIG. 6 b, the gasstation 610 is assigned visibility value of 1 for clearly visible fromroad segments 620, 622, 624, 626 and 628. In alternative embodiments,different visibility values may be used. For example, the level ofvisibility may be selected based on the percentage of the road segmentthat the feature is visible.

The seasonal dependency attribute indicates whether the feature isimpacted during a specific time period. In one embodiment, thegeographic researcher indicates yes or no as to whether a seasonaldependency exists and records the season or time period during which thefeature is impacted. For example, the lake 600 of FIG. 6 a freezesduring the winter and may be covered with snow rendering itunrecognizable, so the researcher indicates a yes for seasonaldependency for the lake 600 during the winter. Additionally, a swimmingpool would be difficult to recognize during non-summer months because itis closed, so the swimming pool would also be classified as a yes forseasonal dependency during the non-summer months. Furthermore, in thesummer the visibility of a building may be less due to trees andflowers.

The relative distance attribute indicates a perceived distance betweenthe feature and the guidance feature point object location consideringfactors of the local situation, visibility and size of the feature. Therelative distance provides a prominence of the feature, such as howprominent the feature is in its surroundings. In one embodiment, a valueof 1 is assigned for features relatively close to the guidance featurepoint object location, and a value of 2 is assigned for featuresrelatively distant to the guidance feature point object location. Forexample, a large Cathedral located 100 meters from the guidance featurepoint object location is considered relatively close; a small caélocated 20 meters from the guidance feature point object location isconsidered relatively distant; and a large lake located 100 meters fromthe guidance feature point object location is considered relativelyclose.

The geographic researcher may also identify and record a permanencerating for the feature indicating whether the appearance or visibilityof the feature will change or is constant. In one embodiment, a value of1 is assigned for features with low permanence that are expected tochange within one year, a value of 2 is assigned for features withmedium permanence that are expected to change between one year and threeyears, a value of 3 is assigned for features with high permanence thatare not expected to change within three years or more. For example, alarge Cathedral is given a high permanence value; a small café is givena low permanence rating because of the likelihood it will close withinone year.

The geographic researcher may also identify and record a feature extentrating for the feature indicating the length of the feature. In oneembodiment, a value of 1 is assigned for feature extent length less than25 meters, a value of 2 is assigned for feature extent length between 25and 50 meters, a value of 3 is assigned for feature extent lengthbetween 50 and 75 meters, and a value of 4 is assigned for featureextent length greater than 75 meters. For example, a large Cathedral isgiven a feature extent value of 4 because its extent exceeds 75 meters;a small café is given a feature extent value of 1 because its extent isless that 25 meters.

The geographic research may also identify and record additionalinformation that indicates the importance of the feature. For example, auniqueness rating indicates generally how visually different or visuallydistinctive the feature is as compared to surround features. Theuniqueness rating may be a value of 1 for no difference, value of 2 forsome difference and a value of 3 for totally unique. For example, athirty story sky scraper surrounded by single story buildings would havea value of 3. The uniqueness rating considers visually distinctiveelements of the feature, such as the shape of the building, color of thebuilding or building materials. For example, a yellow glass buildingamong white brick buildings would have a value of 3.

At step 510, the geographic researcher computes a calculated importancevalue indicating a rating of the importance of the feature for routeguidance. A feature is important for route guidance because it isreadily recognizable or readily visually distinguishable from itssurroundings. FIG. 7 illustrates a table 700 showing one exemplaryembodiment for computing the calculated importance value. The tableincludes columns for attributes 702, values 704, scores 706 and weights708. The attributes of visibility 710, permanence 712, relative distance714, feature extent 716, seasonal dependency 718 and preferred name 720are included in the table. For the attribute of preferred name, a valueof 1 indicates that there is no preferred name for the feature; a valueof 2 indicates that a preferred name for the feature is available, suchas pink square building. The table 700 includes a score for each of thevalues of each attribute. For example, a score of 2 is provided for thevisibility value of 1 clearly visible.

Referring to FIG. 7, the table 700 also includes weights 708 for eachattribute. In this exemplary embodiment, the weights all have a value of1; however, these weights may have different values in otherembodiments. For example, there may be different weight values fordifferent end users, such as trucks, passenger cars, pedestrians, males,females, tourists and local residents. The calculated importance valueis computed as the sum of the product of the score and weight of eachattribute. For the exemplary embodiment, the calculated importance valuewill be a number less than or equal to ten. For example, the Cathedralhas a visibility value of 1 with score 2 and weight 1; a permanencevalue of 3 with score 2 and weight 1; a relative distance value of 1with score 1 and weight 1; a feature extent value of 4 with score 3 andweight 1; a seasonal dependence value of 1 with score 0 and weight 1;and a preferred name value of 2 with score 2 and weight 1 providing acalculated importance value of 10 (2*1+2*1+1*1+3*1+0*1+2*1=10).

At step 512, the guidance feature point object information, associationinformation, importance attribute information and calculated importanceare stored in the geographic database. The geographic database is storedon a computer readable medium.

IV. Geographic Database with Guidance Feature Points and AssociationData

The guidance feature point objects, association data, importanceattributes and calculated importance information collected as describedabove is included in the geographic database 116 that represents some ofthe physical geographic features in the geographic region 202. In theexemplary embodiment of FIG. 3, the geographic database 116 thatrepresents the geographic region 202 contains at least one guidancefeature point database record 314 for each guidance feature point objectidentified in the geographic region 202. The geographic database 116also includes association data records 316 to provide associationsbetween the guidance feature point objects, attributes of the guidancefeature point objects and other database records.

FIG. 8 shows some of the components of a guidance feature point databaserecord 314 and an association database record 316 contained in thegeographic database 116. The guidance feature point database record 314includes a guidance feature point ID 314(1) by which the data record canbe identified in the geographic database 116. Each guidance featurepoint database record 314 has associated with it information (such as“attributes”, “fields”, etc.) that describes features of the guidancefeature point object. The guidance feature point database record 314 mayinclude data 314(2) that indicate a type of guidance feature pointobject, such as a type used for natural guidance that providescontextual environmental information.

The guidance feature point data record 314 includes data 314(3) thatindicate the road segment ID on or at which the guidance feature pointobject is located. The guidance feature point object data record 314includes data indicating a side 314(4) of the road segment that theguidance feature point object is located. The data indicating a side314(4) provides that the feature is to the left or right side relativeto a reference node of the road segment. Additionally, side data 314(4)may indicate neither side for when the feature is equally visible onboth sides of the road segment. The guidance feature point data record314 further includes location data 314(5) indicating the longitude andlatitude (and altitude) of the guidance feature point object.

The association database records 316 provide a feature association modelthat defines an association or relationship between two or more databaserecords selected from road segment database records 304, node databaserecords 306, complex feature database records 308, cartographic featuredatabase records 310, point of interest database records 312 andguidance feature point object database records 314. The associationmembers for the context of natural guidance include a road segmentassociated with a guidance feature point object, a point of interestassociated with a road segment and a guidance feature point object, acartographic feature associated with a road segment and a guidancefeature point object, a complex feature associated with a road segmentand a guidance feature point object, and a node associated with a roadsegment and a guidance feature point object.

Each association database record 316 includes an ID 316(1) by which thedata record can be identified in the geographic database 116. Theassociation database record 316 includes data 316(2) that indicate atype of association, either for passing guidance or for junctionguidance. The feature association for passing guidance associates aguidance feature point object and a road segment to support routeguidance when driving on the road segment and passing the visiblefeature corresponding to the guidance feature object point. The featureassociation for junction guidance associates a guidance feature pointobject and a road segment to support route guidance when driving orturning over a junction or complex intersection. In the context of onemaneuver over a junction or complex intersection, the featureassociations are defined for the road segment that is connected to thejunction or complex intersection prior to the specific maneuver over thejunction or complex intersection.

Although not shown in FIG. 8, the association data 316 may furtherinclude data that links the association data record 316 to the roadsegment database record 304 by identifying the respective association ID316(1) and road segment ID 304(1), links the association data record 316to the node data record 306 by identifying the respective association ID316(1) and node ID 306(1), links the association data record 316 to thecartographic feature database record 310 by identifying the respectiveassociation ID 316(1) and an ID of cartographic feature, links theassociation data record 316 to the complex feature database record 398by identifying the respective association ID 316(1) and an ID of thecomplex feature, links the association data record 316 to the point ofinterest database record 312 by identifying the respective associationID 316(1) and ID of the point of interest, and links the associationdata record 316 to the guidance feature point data record 314 byidentifying the respective association ID 316(1) and guidance featurepoint object ID 314(1).

As shown in FIG. 8, the association data also includes attributeinformation of associated name data 802. The associated name data 802includes an ID 802 (1) by which the name data record 802 can beidentified in the geographic database 116. The associated name databaserecord 802 includes data 802(2) that indicate a preferred name whenexplicating the associated feature during guidance. The preferred namedescribes a visible characteristic or a visually distinguishing aspectof the feature, such as the color of the feature, shape of the feature,age of the feature, building materials of the feature, style of thefeature, architectural description, decorative features, other visualproperties including luster and sheen (shiny or dull) of the feature,motion or perceived motion of a portion of the feature, and/or anyvisible attribute that distinguishes the feature from other features inthe surrounding area. For example, the special name may be pinkbuilding, red building, dome-shaped building, short-fat building, glassbuilding, brick building, gothic architecture building, windowlessbuilding, tall building, neon sign of a bird attached to building,fountain in front of building, sculpture in front of building, and soon. In one embodiment, the preferred name may be a locally know name ornickname for the feature, such as “Max Brothers Petrol Shop.”Alternatively, the preferred name is a base name, such as gas station,or a brand name. In one embodiment, more than one preferred name may beincluded in data 802(2), such as different preferred names for differentend users (male, female, tourist and local resident).

Referring to FIG. 8, the association data also includes associatedimportance data record 804. The associated importance data record 804contains several attributes useful for determining whether to use theassociated feature when providing a guidance message. A feature isimportant for route guidance because it is readily recognizable orreadily visually distinguishable from its surroundings. The associatedimportance data 804 includes an ID 804(1) by which the data record canbe identified in the geographic database 116. The associated importancedatabase record 804 includes data 804(2) that indicate an applieddirection of the association. The direction is specified as a positivedirection from a reference node to a non-reference node, negativedirection from the non-reference node to the reference node or bothdirections.

The associated importance database record 804 includes data 804(3) thatindicate a visibility of the feature from the direction of theassociated road segment. The visibility may indicate clearly visible,partially visible or not visible and provide values rating the level ofvisibility or the level of visual obstruction. The associated importancedatabase record 804 includes data 804(4) that indicate the seasonaldependency of whether (yes or no) the importance of the feature isimpacted during a season or during a specific period of time. Theseasonal dependence attribute can be used to determine the relevance ofa feature for route guidance related to the season of the year or to acertain time of the year. In one embodiment, the seasonal dependencydata 804(4) indicates a specific time period that the visibility of thefeature is impacted, such as winter.

The associated importance database record 804 includes data 804(5) thatprovide a relative distance attribute that indicates the perceiveddistance between the feature and the guidance location. The relativedistance provides a prominence of the feature, such as how prominent thefeature is its surroundings. The relative distance attribute indicateswhether the feature is close or distant, and it is an interpreted valuethat depends on the local situation, visibility and size of the feature.For example, a Cathedral located 100 meters from the road segment isconsidered to be close while a small café located 25 meter from the roadsegment is considered to be distant.

The associated importance database record 804 may include other data804(6). Other data include a permanence rating for the featureindicating whether the appearance or visibility of the feature willchange or is constant, a feature extent rating for the featureindicating the length of the feature, a preferred name for the featureand a uniqueness rating for the feature indicating how different ordistinctive the feature is from surrounding features. In an exemplaryembodiment, values for the importance attributes correspond to thevalues described about in conjunction with FIG. 7.

The associated importance database record 804 also includes calculatedimportance data 804(7). The calculated importance data 804(7) is arating on the scale of 0 to 10 of the importance of the feature forroute guidance, the higher the rating the more relevant the feature isfor route guidance. The calculated importance can be used to determinethe relevance of a feature for route guidance. A feature is importantfor route guidance because it is readily recognizable or readilyvisually distinguishable from its surroundings. When a maneuver hasmultiple features available to reference, the feature with the highestcalculated importance is selected. The calculated importance may becomputed using the visibility 804(3), seasonal dependency 804(4),relative distance 804(5), availability of a preferred name 802(2) aswell as other attribute such as described above in conjunction with FIG.5. In an exemplary embodiment, the values, scores and weights for thecalculated importance correspond to those described about in conjunctionwith FIG. 7.

V. Route Calculation and Route Guidance

As discussed above in conjunction with FIG. 1, the navigation system 100includes navigation application software programs 110 that provide thevarious navigation features and functions. In one embodiment, thenavigation functions and features may include route calculation 124. Theroute calculation function 124 receives a request to calculate a routeto a desired destination. The request may be in the form of anidentification of a starting location and a desired destinationlocation. The identification of these locations may include thegeographic coordinates of these locations. The route calculationfunction may also be provided with other data or parameters, such asroute preferences. Given at least the identification of the startinglocation and the destination location, the route calculation function124 determines one or more solution routes between the starting locationand the destination location. A solution route is formed of a series ofconnected road segment over which the end user can travel from thestarting location to the destination location.

When the route calculation function 124 calculates a route, it accessesthe geographic database 116 and obtains the road segment data records304 and/or other data. The route calculation function 124 may usevarious means or algorithms in determining solution routes. Methods forroute calculation are disclosed in U.S. Pat. No. 6,192,314, the entiredisclosure of which is incorporated by reference herein. (The methodsdisclosed in the aforementioned patent represent only some of the waysthat routes can be calculated and the claimed subject matter herein isnot limited to any particular method of route calculation. Any suitableroute calculation method now known or developed in the future may beemployed.)

The route calculation function 124 provides an output. In oneembodiment, the output of the route calculation function 124 is in theform of an ordered list identifying a plurality of road segments, suchas the road segment IDs 304(1) (i.e., seg1, seg2, seg3, . . . , seg(E),seg(F)) from the geographic database 116. The plurality of road segmentIDs 304(1) represents the road segments that form the continuousnavigable route between the origin and the destination that had beencalculated by the route calculation function 124. (The route calculationfunction 124 may calculate more than one solution route.)

The route guidance function 126 uses the output of the route calculationfunction 124 to generate detailed directions or guidance messages forfollowing the calculated route. In an exemplary embodiment, the routeguidance function 126 evaluates each of the road segments that comprisethe calculated route and prepares passing guidance messages and junctionguidance messages. Passing guidance messages provide directions andenvironmental cues when driving the road segment and passing a visiblefeature. Junction guidance messages provide maneuver directions andenvironmental cues when driving or turning over a junction or complexintersection. The guidance messages may be prepared before the route istraveled or during travel of the route. The passing guidance message andjunction guidance message may be provided for each component roadsegment of the route or only for a subset thereof. The guidance messagesare generally required at decision points along the route that require amaneuver.

FIG. 9 a illustrates a flow chart of the steps for providing passingguidance for one of the road segments of the calculated route. At step900, the guidance function 126 identifies all guidance feature pointobjects associated with the road segment. In the exemplary embodiment,the guidance function 126 identifies the guidance feature point objectsassociated with the road segments using the association data 316 of thegeographic database 116 that provides the guidance feature point objectslocated on the road for passing guidance. FIG. 9 b illustrates a roadsegment 910 that has two guidance feature point objects located on theroad segment 910. A guidance feature point object 912 is associated witha hospital building 914 and a guidance feature point object 918 isassociated with a lake 916.

At step 902 of FIG. 9 a, the guidance function 126 determines which oneof the guidance feature point objects located at the road segment hasthe highest associated importance. A feature is important for routeguidance because it is readily recognizable or readily visuallydistinguishable from its surroundings. In one embodiment, the guidancefunction 126 obtains the calculated importance value 804(7) from thegeographic database 116 for each of the guidance feature point objectslocated at the road segment. For example, the hospital 914 has acalculated importance value of eight while the lake 916 has a calculatedimportance value of six. Accordingly, the hospital 914 has the highestcalculated importance value, so the hospital 914 will be used whengenerating the passing guidance message rather than the lake 916.

In another embodiment, the guidance function 126 obtains and evaluatesthe importance attributes 804 for each of the guidance feature pointobjects located at the road segment. The importance attributes includevisibility 804(3), seasonal dependency 804(4), relative distance 804(5)and other data 804(6), such as a permanence rating for the featureindicating whether the appearance or visibility of the feature willchange or is constant, a feature extent rating for the featureindicating the length of the feature, a preferred name exists for thefeature, and an uniqueness rating indicates how visually different ordistinctive the feature is compared to surrounding features. Theguidance function 126 calculates an importance rating or value for eachof the features associated with the guidance feature point objectslocated at the road segment using some or all of the importanceattributes. The calculation may be similar to that described above inconjunction with FIG. 7 or a different calculation. Additionally, thescores for each attribute and weights for each may be different thandescribed in conjunction with FIG. 7. For example, the scores andweights may be modified based on the type of end user, such as a truckthat provides a higher point of view or a pedestrian that moves at slowspeed, female/male end user, or tourist or local resident.

At step 904, the guidance function 126 generates a guidance messageusing the preferred name of the feature associated with the highestimportance guidance feature object point. For the example shown in FIG.9 b, the hospital 914 (and its guidance feature point object 912) wasfound to have the highest importance rating, so the guidance messagewill reference the hospital 914. In the exemplary embodiment, theguidance function 126 obtains the name 802(2) from the geographicdatabase 116. For example, the hospital 914 has a preferred name of“tall blue glass building” that identifies its glass building materialand greater height compared to the surrounding buildings. In otherembodiments, the preferred name may be the words that describe visiblecharacteristics or visually distinguishing element of the feature, suchas the color, shape, age, building material, size, architectural style,decorative feature, luster, motion and/or any visible attribute thatdistinguishes the feature from other features in the surrounding area.For example, the special name may be pink building, red building,dome-shaped building, glass building, brick building, gothicarchitecture building, windowless building, tall building, neon sign ofa bird attached to building, fountain in front of building, sculpture infront of building, and so on. In another embodiment, the preferred namemay be a locally know name or nickname for the feature, such as“south-side hospital.” In one embodiment, the guidance function 126chooses from more than one available preferred name based oncharacteristics of the end user, such as a preferred name for a femaleend user.

For the road segment 910 shown in FIG. 9 b, the guidance message is“follow the road passing the tall blue glass building on your left.” Atstep 906, this passing guidance message is provided via the userinterface 114 of the navigation system 100 when passing the location ofthe associated guidance feature point object 912 for the hospital 914.The guidance message may be provided on the display associated with theuser interface 114 or as an audio message from a speaker associated withthe user interface 114

FIG. 10 illustrates a flow chart of the steps for providing junctionguidance for transition from one of the road segment to another roadsegment of the calculated route at a junction or complex intersection.At step 1000, the guidance function 126 identifies all guidance featurepoint objects associated with the road segment prior to the junction orcomplex intersection. In the exemplary embodiment, the guidance function126 identifies the guidance feature point objects associated with theroad segment using the association data 316 of the geographic database116.

FIG. 11 illustrates a route 1100 that travels through road segment 1102and requires a left turn maneuver onto road segment 1104. The roadsegment 1102 has two associated guidance feature point objects. Aguidance feature point object 1106 is associated with a courthouse 1108and a guidance feature point object 1110 is associated with a gasstation 1112 both are visible from the road segment 1102.

At step 1002 of FIG. 10, the guidance function 126 determines which oneof the guidance feature point objects associated with the road segment1102 has the highest importance. In one embodiment, the guidancefunction 126 obtains the calculated importance value 804(7) from thegeographic database 116 for each of the guidance feature point objects1106 and 1110 associated with the road segment 1102. For example, thecourthouse 1108 has a calculated importance value of seven while thelake gas station 1112 has a calculated importance value of five.Accordingly, the courthouse 1108 has the highest calculated importancevalue, so the courthouse 1108 will be used when generating the junctionguidance message rather than the gas station. In another embodiment, theguidance function 126 obtains and evaluates the importance attributes804 for each of the guidance feature point objects 1106 and 1110associated with the road segment 1102 in the manner similar to thatdescribe above for passing guidance.

At step 1004, the guidance function 126 generates a guidance messageusing the preferred name of the feature associated with the highestimportance guidance feature point object. For the example shown in FIG.11, the courthouse 1108 (and its guidance feature point object 1106) wasfound to have the highest importance rating, so the guidance messagewill reference to the courthouse 1108. In the exemplary embodiment, theguidance function 126 obtains the name 802(2) from the geographicdatabase 116.

For example, the courthouse 1108 has a preferred name of “grand old,white marble building” that identifies its color, building material,style and age compared to the surrounding buildings. In anotherembodiment, the preferred name may be a locally know name for thefeature, such as “old jail.”

For the road segment 1102 shown in FIG. 11, the guidance message is“turn left directly after the grand old, white marble building.” At step1006, this junction guidance message is provided via the user interface114 of the navigation system 100 prior to the location of the requiredmaneuver. For the illustrative case, the message is provided whenpassing the location of the associated guidance feature point object1106 for the courthouse 1108 prior to the intersection.

In another embodiment, the guidance function 126 may considerreferencing traffic signal and stop signs when providing junctionguidance messages. The traffic signals and/or stop signs are alsofeatures visible from the road segment prior to a maneuver. In oneembodiment, the geographic database 116 includes data representing thetraffic signal and stops sign located at the junction visible from theroad segment, as well as a calculated importance value for referencingthe traffic signal (and/or stop sign). Similar to the calculatedimportance value described above, the calculated importance value forthe traffic signal (and/or stop sign) is a value from 0 to 10 with 0representing low importance and 10 representing high importance forguidance. The database may further include importance indicatorattributes of type of signal (timed, turn arrow, traffic light, stopsign), placement of signal (left side, right side, overhead) andurban/rural general location (urban stop signs are less visible thanrural stop signs). The importance indicator attributes of the trafficsignal (and/or stop sign) may also be used to determine the visibilityand relevance of traffic signal (and/or stop sign). When the guidancefunction 126 determines which one of the guidance feature point objectsassociated with the road segment has the highest importance, theguidance function also obtains or computes the calculated importancevalue for the traffic signal (and/or stop sign). For the example of FIG.11, if the traffic signal at the intersection has a calculatedimportance value greater than that of the courthouse, the guidancemessage would be “turn left at the traffic lights.”

It is intended that the foregoing detailed description be regarded asillustrative rather than limiting and that it is understood that thefollowing claims including all equivalents are intended to define thescope of the invention. The claims should not be read as limited to thedescribed order or elements unless stated to that effect. Therefore, allembodiments that come within the scope and spirit of the followingclaims and equivalents thereto are claimed as the invention.

We claim:
 1. A computer-implemented method of collecting data for ageographic database for use with a navigation system comprising:identifying a feature visible from a first road segment; defining aguidance feature point object at a location at the first road segmentwhere the identified feature is most visibly prominent; determining animportance rating for the identified feature indicating a level ofvisual distinctiveness as compared to other features surrounding theidentified feature; determining a preferred name for the identifiedfeature, wherein the preferred name is selected from a group consistingof a color of the identified feature, a building material of theidentified feature, a shape of the identified feature, an architecturalstyle of the identified feature, and a decorative element of theidentified feature; storing data representing the guidance feature pointobject in a geographic database on the computer readable medium; storingthe importance rating for the identified feature in the geographicdatabase on the computer readable medium; and storing the preferred namefor the identified feature in the geographic database on the computerreadable medium.
 2. The method of claim 1 wherein the step ofdetermining the importance rating considers a level of visibilityobstruction of the identified feature from the location of the guidancefeature object point.
 3. The method of claim 1 wherein the step ofdetermining the importance rating considers a likelihood that a visibleappearance of the identified feature will change.
 4. The method of claim1 wherein the step of determining the importance rating considerswhether a visible appearance of the identified feature is impacted by aseason.
 5. The method of claim 1 wherein the step of determining theimportance rating considers both a size of the identified feature and adistance of the identified feature from the road segment.
 6. The methodof claim 1 wherein the step of determining the importance ratingconsiders a length of the identified feature.
 7. The method of claim 1wherein the location of the guidance feature point object is not at anentrance to the identified feature.
 8. The method of claim 1 wherein thelocation of the guidance feature point object is not at an address pointlocation of the identified feature.
 9. The method of claim 1 furthercomprising: identifying a second road segment from which the feature isvisible; and storing data in the geographic database that associates thesecond road segment with the guidance feature point object.
 10. Acomputer-implemented method of collecting data for a geographic databasefor use with a navigation system comprising: identifying a featurevisible from a first road segment; defining a guidance feature pointobject at a location at the first road segment where the identifiedfeature is most visibly recognizable; collecting at least one importanceattribute selected from a group consisting of a permanence attributerepresenting a likelihood that a visible appearance of the identifiedfeature is constant, a seasonal dependency attribute representingwhether the visible appearance is impacted by a season, a visibilityattribute representing a level of visibility obstruction, a relativedistance attribute representing a visual prominence considering both asize of the identified feature and a distance of the identified featurefrom the first road segment, a feature extent attribute representing alength of the identified feature, and a preferred name attributerepresenting a name describing a visually distinguishing aspect of theidentified feature; storing data representing the guidance feature pointobject in the geographic database on a computer readable medium; andstoring the importance attribute for the identified feature in thegeographic database on the computer readable medium.
 11. The method ofclaim 10 further comprising: computing a calculated importance valuerepresenting the importance of the identified feature for route guidancewhen traveling the first road segment; and storing the calculatedimportance value for the identified feature in the geographic databaseon the computer readable medium.
 12. The method of claim 11 wherein thestep of computing the calculated importance value considers at least twoof the importance attributes and applies at least two weighing factors.13. The method of claim 11 wherein the step of computing the calculatedimportance value uses a score associated with one of the correspondingimportance attributes and applies a weighing factor.
 14. The method ofclaim 10 further comprising: determining a preferred name for theidentified feature, wherein the preferred name is selected from a groupconsisting of a color of the identified feature, a building material ofthe identified feature, a shape of the identified feature, anarchitectural style of the identified feature, a decorative element ofthe identified feature, and a local nickname of the identified feature;and storing the preferred name for the identified feature in thegeographic database on the computer readable medium.
 15. The method ofclaim 10 further comprising: identifying a second road segment fromwhich the feature is visible; and storing data in the geographicdatabase that associates the second road segment with the guidancefeature point object.
 16. A computer-implemented method of collectingdata for a geographic database for use with a navigation systemcomprising: identifying a feature visible from a road segment; defininga guidance feature point object at a location at the road segment wherethe identified feature is most useful for guidance; determining apreferred name for the identified feature, wherein the preferred name isselected from a group consisting of a color of the identified feature, abuilding material of the identified feature, a shape of the identifiedfeature, an architectural style of the identified feature, a decorativeelement of the identified feature, and a nickname of the identifiedfeature; storing data representing the guidance feature point object inthe geographic database on a computer readable medium; and storing thepreferred name for the identified feature in the geographic database onthe computer readable medium.
 17. The method of claim 16 furthercomprising: collecting at least one importance attribute selected from agroup consisting of a permanence attribute representing a likelihoodthat a visible appearance of the identified feature is constant, aseasonal dependency attribute representing whether the visibleappearance is impacted by a season, a visibility attribute representinga level of visibility obstruction, a relative distance attributerepresenting a visual prominence considering both a size of theidentified feature and a distance of the identified feature from thefirst road segment, a feature extent attribute representing a length ofthe identified feature, and a preferred name attribute representing aname describing a visually distinguishing aspect of the identifiedfeature; and storing the importance attribute for the identified featurein the geographic database on the computer readable medium.
 18. Themethod of claim 16 further comprising: computing a calculated importancevalue representing the importance of the identified feature for routeguidance when traveling the road segment; and storing the calculatedimportance value for the identified feature in the geographic databaseon the computer readable medium.
 19. The method of claim 16 wherein thelocation of the guidance feature point object is not at an access pointto the feature.
 20. The method of claim 16 wherein the location of theguidance feature point object is not at an address point location of thefeature.